U.S. patent application number 11/435867 was filed with the patent office on 2006-11-23 for polypropylene silicate nanocomposites.
This patent application is currently assigned to Cornell Research Foundation, Inc.. Invention is credited to Xiao-Ping Chen, Geoffrey W. Coates, Hyuk Lee, Dotsevi Y. Sogah.
Application Number | 20060260677 11/435867 |
Document ID | / |
Family ID | 37447204 |
Filed Date | 2006-11-23 |
United States Patent
Application |
20060260677 |
Kind Code |
A1 |
Sogah; Dotsevi Y. ; et
al. |
November 23, 2006 |
Polypropylene silicate nanocomposites
Abstract
Nanoadditive is constituted of organophilic polymer or copolymer
covalently bonded by linking group to silicate and is blended with
polypropylene to produce nanocomposite which is useful in all cases
where polypropylene is used and resists breakage and is not
flammable and has improved barrier properties compared to neat
polypropylene.
Inventors: |
Sogah; Dotsevi Y.; (Ithaca,
NY) ; Chen; Xiao-Ping; (Bellmore, NY) ; Lee;
Hyuk; (Seoul, KR) ; Coates; Geoffrey W.;
(Ithaca, NY) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE
FOURTH FLOOR
ALEXANDRIA
VA
22314
US
|
Assignee: |
Cornell Research Foundation,
Inc.
Ithaca
NY
|
Family ID: |
37447204 |
Appl. No.: |
11/435867 |
Filed: |
May 18, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60683346 |
May 23, 2005 |
|
|
|
Current U.S.
Class: |
136/253 |
Current CPC
Class: |
C08L 51/06 20130101;
C08L 23/10 20130101; C08L 2666/24 20130101; C08L 23/145 20130101;
C08L 23/10 20130101 |
Class at
Publication: |
136/253 |
International
Class: |
H01L 31/00 20060101
H01L031/00 |
Goverment Interests
[0002] This work was supported at least in part by the Cornell
Center for Materials Research, a National Science Foundation-funded
MSERC (DMR-0079992). The government has certain rights in the
invention.
Claims
1. Nanoadditive comprising organophilic polymer or copolymer
covalently bonded via a linking group to silicate, where the
silicate content ranges from 5% to 50% by weight.
2. The nanoadditive of claim 1 where the silicate content ranges
from 15 to 30% by weight.
3. The nanoadditive of claim 2 where the linking group comprises
reaction product of group A of group A functionalized organophilic
polymer or copolymer and group B of group B functionalized
silicate.
4. The nanoadditive of claim 3 where group A is selected from the
group consisting of epoxide, cyclic anhydride, lactone, amine,
alcohol and acid containing moieties and group B is selected from
the group consisting of alkoxide, amine, acid, ester, aldehyde,
ketone, and lactone containing moieties; where when group A is
epoxide containing moiety, group B is selected from the group
consisting of alkoxide, amine and acid containing moieties; where
when group A is cyclic anhydride containing moiety, group B is
selected from the group consisting of alkoxide and amine containing
moieties; where when group A is lactone containing moiety, group B
is selected from the group consisting of alkoxide and amine
containing moieties; where when group A is amine containing moiety,
group B is selected from the group consisting of acid, ester,
aldehyde, ketone and lactone containing moieties; where when group
A is alcohol containing moiety, group B is selected from the group
consisting of acid, ester, aldehyde, ketone, and lactone containing
moieties; and when group A is acid containing moiety, group B is
selected from the group consisting of alkoxide and amine containing
moieties.
5. The nanoadditive of claim 4 where the group B is anchored to
silicate by an ammonium group separated from group B by an organic
spacer moiety containing from 1 to 36 carbon atoms.
6. The nanoadditive of claim 3 where the polymer or copolymer is
poly(C.sub.2-C.sub.4-.alpha.-olefin-co-hexadiene) copolymer having
M.sub.n ranging from 5,000 to 2,000,000 grams per mole and PDI
ranging from 1.1 to 3.
7. The nanoadditive of claim 6 where the group A functionalized
polymer or copolymer is epoxide functionalized poly
(propylene-co-hexadiene).
8. The nanoadditive of claim 4 where the polymer or copolymer is
poly(propylene-co-hexadiene) having M.sub.n ranging from 5,000 to
2,000,000 grams per mole.
9. The nanoadditive of claim 4 where the polymer or copolymer is
polypropylene having M.sub.n ranging from 5,000 to 4,000,000 grams
per mole.
10. The nanoadditive of claim 4 where the group A functionalized
polymer or copolymer is cyclic anhydride functionalized said
polypropylene.
11. The nanoadditive of claim 4 where the group A functionalized
polymer or copolymer is commercially available expoxide
functionalized organophilic polymer or copolymer.
12. The nanoadditive of claim 10 where the group A functionalized
polymer or copolymer is glycidyl methacrylate having M.sub.n
ranging from 5,000 to 1,000,000 grams per mole.
13. Nanocomposite comprising from 99 to 90% by weight polypropylene
having M.sub.n ranging from 5,000 to 4,000,000 grams per mole, and
from 1 to 10% by weight nanoclay where silicate layers are
exfoliated and the degree of exfoliation is preserved despite
extrusion at 200.degree. C. and microinjection at 230.degree.
C.
14. The nanocomposite of claim 13 comprising from 98 to 90% by
weight of the polypropylene and 2 to 10% by weight of the
nanoclay.
15. Nanocomposite comprising from 99 to 90% by weight polypropylene
having M.sub.n ranging from 5,000 to 4,000,000 grams per mole, and
1 to 10% by weight namely where toughness is increased at least 10%
while Young's modulus is decreased less than 15%, compared to neat
polypropylene.
16. The nanocomposite of claim 15 comprising from 98 to 90% by
weight of the polypropylene and from 2 to 10% of the nanoclay.
17. Nanocomposite comprising the nanoadditive of claim 1 blended
polypropylene having M.sub.n ranging from 5,000 to 4,000,000 grams
per mole, with the weight ratio of said polypropylene to said
nanoadditive ranging from 20:1 to 1:1.
18. Nanocomposite comprising the nanoadditive of claim 4 blended
with polypropylene having M.sub.n ranging from 5,000 to 4,000,000
grams per mole, with the weight ratio of said polypropylene to said
nanoadditive ranging from 20:1 to 1:1.
19. Nanocomposite comprising the nanoadditive of claim 7 blended
with polypropylene having M.sub.n ranging from 5,000 to 4,000,000
grams per mole, with the weight ratio of said polypropylene to said
nanoadditive ranging from 20:1 to 1:1.
20. Nanocomposite comprising the nanoadditive of claim 10 blended
with polypropylene having M.sub.n ranging from 5,000 to 4,000,000
grams per mole, with the weight ratio of said polypropylene to said
nanoadditive ranging from 20:1 to 1:1.
21. Epoxy functionalized poly(propylene-co-hexadiene) copolymer
having M.sub.n ranging from 5,000 to 2,000,000 grams per mole and
PDI ranging from 1.1 to 3.
22. A method for preparing a nanoadditive comprising the step of
reacting group A functionalized organophilic polymer or copolymer
with group B functionalized silicate where group A and group B
react to form silicate covalently bonded to the polymer or
copolymer.
23. The method of claim 22 where group A is selected from the group
consisting of epoxide, cyclic anhydride, lactone, amine, alcohol
and acid containing moieties and group B is selected from the group
consisting of alkoxide, amine, acid, ester, aldehyde, ketone, and
lactone containing moieties; where when group A is epoxide
containing moiety, group B is selected from the group consisting of
alkoxide, amine and acid containing moieties; where when group A is
cyclic anhydride containing moiety, group B is selected from the
group consisting of alkoxide and amine containing moieties; where
when group A is lactone containing moiety, group B is selected from
the group consisting of alkoxide and amine containing moieties;
where when group A is amine containing moiety, group B is selected
from the group consisting of acid, ester, aldehyde, ketone and
lactone containing moieties; where when group A is alcohol
containing moiety, group B is selected from the group consisting of
acid, ester, aldehyde, ketone, and lactone containing moieties; and
when group A is acid containing moiety, group B is selected from
the group consisting of alkoxide and amine containing moieties.
24. The method of claim 23 where the group A functionalized polymer
or copolymer is epoxide functionalized poly(propylene-co-hexadiene)
having M.sub.n ranging from 5,000 to 2,000,000 grams per mole and
PDI ranging from 1.1 to 1.3.
25. The method of claim 24 where the group B functionalized
silicate is 12-aminododecanoic acid or glycine or
poly(propylenegylcol)bis(2-aminopropyl ether) ion exchanged under
acidic conditions with Na-MMT so that group B is anchored to
silicate by an ammonium group.
26. The method of claim 22 where the group A functionalized polymer
or copolymer is cyclic anhydride functionalized polypropylene
having M.sub.n ranging from 5,000 to 4,000,000.
27. The method of claim 25 where the group B functionalized
silicate is 12-aminododecanoic acid or glycine or
poly(propyleneglycol)bis(2-aminopropyl ether) ion exchanged under
acidic conditions with Na-MMT so that group B is anchored to
silicate by ammonium group.
28. A method for preparing a nanocomposite comprising the step of
blending the nanoadditive of claim 1 with polypropylene having
M.sub.n ranging from 5,000 to 4,000,000 grams per mole in a weight
ratio of said polypropylene to said nanoadditive ranging from 20:1
to 1:1.
29. A method for preparing a nanocomposite comprising the step of
blending the nanoadditive of claim 3 with polypropylene having
M.sub.n ranging from 5,000 to 4,000,000 grams per mole in a weight
ratio of said polypropylene to said nanoadditive ranging from 20:1
to 1:1.
30. A method for preparing a nanocomposite comprising the step of
blending the nanoadditive of claim 6 with polypropylene having
M.sub.n ranging from 5,000 to 4,000,000 grams per mole in a weight
ratio of said polypropylene to said nanoadditive ranging from 20:1
to 1:1.
31. A method for preparing a nanocomposite comprising the step of
blending the nanoadditive of claim 9 with polypropylene having
M.sub.n ranging from 5,000 to 4,000,000 grams per mole in a weight
ratio of said polypropylene to said nanoadditive ranging from 20:1
to 1:1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/683,346, filed May 23, 2005, the whole of
which is incorporated herein by reference.
TECHNICAL FIELD
[0003] This invention is directed at nanocomposite of polypropylene
and nanoclay.
BACKGROUND OF THE INVENTION
[0004] Polypropylene, while very attractive for many uses, has the
disadvantage that its brittleness, flammability and poor gas
barrier properties limit its application. Formation of a polymer
layered silicate nanocomposite is expected to be a practical
approach to enhancing resistance to breakage and to impart
flammability resistance and to improve gas barrier properties.
However, because of its high hydrophobicity, polypropylene is
incompatible with neat hydrophilic clay. Maleic anhydride grafted
polypropylene has been used in place of propylene to increase
compatibility with silicate surface; however, this combination
results in dramatically reduced elongation in comparison to neat
polypropylene. To date, no polypropylene layered silicate
nanocomposite has been reported where elongation was increased
dramatically and toughness was increased while Young's modulus
decreased less than 20%.
SUMMARY OF THE INVENTION
[0005] In one embodiment herein, denoted the first embodiment, the
invention is directed at nanoadditive (masterbatch) useful to
prepare nanocomposites of the second, third and fourth embodiments
of the invention herein, comprising organophilic polymer or
copolymer containing at least one linking group per chain and
covalently bonded via said linking group to silicate, where the
silicate content ranges from 5% to 50% by weight.
[0006] In another embodiment herein, denoted the second embodiment,
the invention is directed to nanocomposite comprising from 99 to
90%, e.g., 98 to 90% by weight polypropylene having M.sub.n ranging
from 5,000 to 4,000,000 grams per mole, and from 1 to 10%, e.g., 2
to 10% by weight nanoclay where silicate layers are exfoliated and
the degree of exfoliation is preserved despite extrusion at
200.degree. C. and microinjection at 230.degree. C.
[0007] In another embodiment herein, denoted the third embodiment,
the invention is directed to nanocomposite comprising from 99 to
90%, e.g., 98 to 90% by weight polypropylene having M.sub.n ranging
from 5,000 to 4,000,000 grams per mole, and from 1 to 10%, e.g., 2
to 10% by weight nanoclay where toughness is increased at least 10%
while Young's modulus is decreased less than 15%, compared to neat
polypropylene. In a preferred case elongation is increased at least
25%.
[0008] In another embodiment herein, denoted the fourth embodiment,
the invention is directed at nanocomposite comprising the
nanoadditive of the first embodiment herein blended with
polypropylene having M.sub.n ranging from 5,000 to 4,000,000 grams
per mole, with the weight ratio of said polypropylene to said
nanoadditive ranging from 20:1 to 1:1.
[0009] In another embodiment herein, denoted the fifth embodiment,
the invention is directed at epoxy or cyclic anhydride or lactone
or amine or alcohol or acid functionalized
poly(propylene-co-hexadiene) copolymer having M.sub.n ranging from
5,000 to 2,000,000 grams per mole and PDI ranging from 1.1 to 3,
useful for preparing nanoadditive of the first embodiment
herein.
[0010] In another embodiment herein, denoted the sixth embodiment,
the invention is directed at a method useful to prepare
nanoadditive of the fifth embodiment herein.
[0011] In another embodiment herein, denoted the seventh
embodiment, the invention is directed at a method useful to prepare
nanocomposite of the second, third and fourth embodiments
herein.
[0012] As used herein, the term "nanocomposite" means composition
of nanoclay (silicate) in a polymer matrix.
[0013] The term "nanoclay" as used herein to means clay having
nanometer thickness silicate platelets that can be modified to make
clay complexes compatible with organic monomers and polymers. The
term "silicate layers" as used herein refers to the nanometer
thickness silicate platelets.
[0014] The term "nanoadditive" is used here to mean a nanocomposite
of nanoclay in a polymer or copolymer where silicate is dispersed
in a matrix of polymer or copolymer for use for blending with
polypropylene to confer increase in elongation and toughness while
preserving Young's modulus, and to confer flammability resistance
and improved barrier properties thereto.
[0015] The "elongation" referred to is sometimes called engineering
strain and is defined as extension per unit length and is
determined using an Instron apparatus and ASTM D638 "Standard test
method for tensile properties of plastics".
[0016] The "toughness" referred to is defined as the area under a
tensile stress strain curve and is determined using an Instron
apparatus and ASTM D638 "Standard test method for tensile
properties of plastics".
[0017] Young's modulus referred to herein means tensile modulus and
is obtained by taking the initial slope of a tensile stress strain
curve determined using an Instron apparatus and ASTM D638 "Standard
test method for tensile properties of plastics".
[0018] The "tensile strength" referred to herein is also known as
tensile or engineering stress and is defined as the force per unit
cross sectional area of the sample and is determined using an
Instron apparatus and ASTM D638 "Standard test method for tensile
properties of plastics".
[0019] M.sub.nand PDI as set forth herein are obtained by high
temperature gel permeation chromatography relative to polystyrene
standards.
DETAILED DESCRIPTION
[0020] We turn now to the first embodiment.
[0021] The linking group comprises for example, reaction product of
group A of group A functionalized organophilic polymer or copolymer
and group B of group B functionalized silicate. The linking group
also comprises an organic spacer moiety comprising 1 to, for
example, 36, carbon atoms and group bonding to silicate where the
organic spacer moiety separates residue of group B from group
bonding to silicate. The group bonding to silicate is preferably
ammonium. There is really no true maximum for the number of carbon
atoms in the organic spacer moiety. For example, the organic spacer
moiety can be polyethylene containing group B and ammonium; a
requirement is that group B functionalization of silicate can occur
in water or acidified water.
[0022] The organophilic polymer or copolymer can be, for example,
(a) poly(C.sub.2-C.sub.4-.alpha.-olefin-co-hexadiene) copolymer
having M.sub.n ranging from 5,000 to 2,000,000 grams per mole and
PDI, for example, ranging from 1.1 to 3, e.g.,
poly(propylene-co-hexadiene), (b) polypropylene having M.sub.n
ranging from 5,000 to 4,000,000 grams per mole, or (c) that of
commercially available group A functionalized organophilic polymer
or copolymer, e.g., that of glycidyl methacrylate having M.sub.n
ranging from 5,000 to 1,000,000 grams per mole.
[0023] The silicate referred to is that of a nanoclay. The nanoclay
is preferably montmorillonite, a naturally occurring nanoclay.
Other useful nanoclays include, for example, fluorohectorite,
laponite, bentonites, beidellites, hectorites, saponites,
nontronites, sauconites, vermiculites, ledikites, nagadiites,
kenyaites and stevensites.
[0024] The nanoclay used for experimentation herein was
Cloisite.RTM. Na.sup.+ obtained from Southern Clay Products, Inc.,
Texas. It is described as a natural montmorillonite and has a dry
particle size of 90% less than 13 microns.
[0025] Group A is preferably selected from the group consisting of
epoxide, cyclic anhydride, lactone, amine, alcohol and acid
containing moieties.
[0026] Group B is preferably selected from the group consisting of
alkoxide, amine, acid, ester, aldehyde, ketone, and lactone
containing moieties.
[0027] When group A is epoxide containing moiety, group B is
selected from the group consisting of alkoxide, amine and acid
containing moieties. When group A is cyclic anhydride containing
moiety, group B is selected from the group consisting of alkoxide
and amine containing moieties. When group A is lactone containing
moiety, group B is selected from the group consisting of alkoxide
and amine containing moieties. When group A is amine containing
moiety, group B is selected from the group consisting of acid,
ester, aldehyde, ketone and lactone containing moieties. When group
A is alcohol containing moiety, group B is selected from the group
consisting of acid, ester, aldehyde, ketone and lactone containing
moieties. When group A is acid containing moiety, group B is
selected from the group consisting of alkoxide and amine containing
moieties.
[0028] A starting point for the epoxide, amine, alcohol and acid
containing moiety functionalized poly(propylene-co-hexadiene)
copolymer is vinyl functionalized poly(propylene-co-hexadiene)
copolymer which is III in WO 2004/067589 A1, the whole of which is
incorporated herein by reference, and its continuation-in-part
published as Publication No. US-2005-0239966-A1. The preparation of
III is described in WO 2004/067589 A1 and US-2005-0239966-A1. The
vinyl functionalized poly(propylene-co-hexadiene) copolymer used in
experiments herein was prepared using a catalyst system of
(F.sub.5-PHI).sub.2 TiCl.sub.2 and MAO as described in WO
2004/067589A1 and polypropylene block is preferably at least 90%,
very preferably at 96%, syndiotactic.
[0029] Epoxide containing moiety functionalized
poly(propylene-co-hexadiene) copolymer is made by reacting the
vinyl functionalized poly(propylene-co-hexadiene) with meta chloro
peroxy benzoic acid (MCPBA). The epoxy functional groups are
preferably present in a block at one end of a chain.
[0030] Amine containing moiety functionalized copolymer can be made
by opening the epoxide with an amine.
[0031] Alcohol containing moiety functionalized copolymer can be
made by opening the epoxide using an amine nucleophile to generate
alcohol moiety.
[0032] Acid, e.g., carboxylic acids, containing moiety
functionalized copolymer can be made by reacting the alcohol
produced in the paragraph directly above with succinic or maleic
anhydride.
[0033] Cyclic anhydride containing moiety functionalized
polypropylene can be made by grafting maleic anhydride to
polypropylene. Cyclic anhydride functionalized polypropylene is
also available commercially. Cyclic anhydride containing moiety
functionalized copolymer can be made by grafting maleic anhydride
to either the polypropylene block or the hexadiene block using
known literature procedures.
[0034] Lactone containing moiety functionalized polypropylene can
be made by grafting an olefin containing lactone to polypropylene.
Lactone containing moiety functionalized copolymer can be made by
grafting an olefin containing lactone to either the polypropylene
block or the hexadiene block using know literature procedures.
[0035] Structure of a vinyl functionalized
poly(propylene-co-hexadiene) copolymer is schematically depicted
below. ##STR1##
[0036] Structure of an epoxide containing moiety functionalized
poly(propylene-co-hexadiene) copolymer is schematically depicted
below. ##STR2##
[0037] Structure of an anhydride containing moiety functionalized
poly(propylene-co-hexadiene) is schematically depicted below.
##STR3##
[0038] Structure for a carboxylic acid containing moiety
functionalized poly(propylene-co-hexadiene) is schematically
depicted below. ##STR4##
[0039] Structure for a lactone containing moiety functionalized
poly(propylene-co-hexadiene) is schematically depicted below.
##STR5##
[0040] We turn now to the group B functionalized silicate.
[0041] It can be, for example, ##STR6## where the ellipse shaped
structure represents nanoclay anion, n ranges from 1 to, for
example, 36,(see comment on polyethylene spacer above), and
R.sup.1, R.sup.11 and R.sup.111 are independently selected from the
group consisting of hydrogen atom and alkyl group containing from 1
to 18 carbon atoms and arylalkyl group containing from 7 to 15
carbon atoms. Structure (III) represents acid containing moiety
functionalized silicate.
[0042] A functionalized silicate (III), can be prepared, for
example, by ion exchanging 12-aminododecanoic acid with nanoclay
(e.g., montmorillonite) in the sodium form under acidic conditions
(e.g., acidified with 1 eq. HCl), in water; or by ion exchanging
glycine (to provide n=1) with nanoclay (e.g., montmorillonite) in
the sodium form (to provide n=11) under acidic conditions (e.g.,
acidified with 1 eq. HCl, in water). As a substitute for
12-aminododecanoic acid or glycine, an amino acid, e.g.,
beta-alanine (n=2) is suitable and almost any long chain with amino
group at one end and acid group at the other is suitable.
[0043] In the case of functionalized silicate (III) there is
produced acid containing moiety functionalized silicate where the
acid containing moiety (a group B residue (i.e., that which remains
of group B after reaction with group A)) is anchored to silicate by
an ammonium group which is separated from group B residue by an
organic spacer moiety containing from 1 to, for example, 36, carbon
atoms.
[0044] In a variation of (III), alkylene is replaced with a
glycol.
[0045] The group B functionalized silicate can also be, for
example, ##STR7## where the ellipse shaped structure represents
nanoclay anion, n ranges from 2 to, for example, 36, and R.sup.1,
R.sup.11 and R.sup.111 are independently selected from the group
consisting of hydrogen atom, alkyl containing from 1 to 18 carbon
atoms and arylalkyl containing from 7 to 15 carbon atoms and R is
selected from the group consisting of hydrogen, alkyl containing
from 1 to 18 carbon atoms, aryl containing from 6 to 20 carbon
atoms and arylalkyl containing from 7 to 15 carbon atoms.
[0046] A functionalized silicate (IV) can be prepared, for example,
by ion exchanging ethylenediamine (to provide n=2) under acidic
conditions with nanoclay (e.g., montmorillonite) in the sodium
form. In addition to ethylenediamine, poly(propylene
glycol)bis(2-aminopropylether), namely
CH.sub.3CH(NH.sub.2)CH.sub.2[OCH.sub.2CH(CH.sub.3)].sub.nNH.sub.2
where n is at least 2 is suitable; in cases where there is a
heteroatom such as O in the spacer as in polyethyleneglycol
(CH.sub.2CH.sub.2O).sub.n, n has to be greater than 1. In
experiments supporting the invention commercially available
poly(propyleneglycol)bis(2-aminopropyl ether where n=5-6
(M.sub.n=400 grams per mole), has been used. The
poly(ethylenegylcol)bis(2-aminopropyl ether)s are water soluble and
have excellent compatibility with a wide range of polar and
water-soluble materials.
[0047] In the case of functionalized silicate (IV), there is
produced amine containing moiety (a group B residue, i.e., that
which remains of group B after reaction with group A) is anchored
to silicate by an ammonium group which is separated from group B
residue by an organic spacer moiety containing from 1 to, e.g., 36,
carbon atoms.
[0048] To form the nanoadditive of the first embodiment, the group
A functionalized organophilic polymer or copolymer can be reacted
with the group B functionalized silicate in solvent, e.g., in
chloroform, or in a melt process. A suitable reaction in solvent is
carried out by refluxing the two components in stoichiometric
amounts for 10-30 hours under nitrogen. A suitable melt process
reaction is carried out by heating an admixture of the two
components in stoichiometric amounts at a temperature ranging, for
example, from 160.degree. to 300.degree. under nitrogen. The
minimum temperature is the melting point and the maximum is set by
the decomposition temperature which is above 400.degree. C.
[0049] In the nanoadditive formation reaction, the organophilic
polymer or copolymer chains become attached to silicate layers by
reaction of group A with group B. This forces more of polymer or
copolymer chains to intercalate between layers of silicate causing
the silicate layers to exfoliate and become randomly dispersed in
the organophilic polymer. As used herein the term "intercalate"
means penetrate. As used herein the term "exfoliate" means become
delaminated. The exfoliated silicate layers provide resistance to
breakage and flammability and improvement in gas barrier property
compared to neat polyethylene.
[0050] We turn now to the second, third and fourth embodiments
herein, i.e., to nanocomposites of the invention herein.
[0051] There nanocomposites can be prepared by blending the
nanoadditive and polypropylene having M.sub.n ranging from 5,000 to
4,000,000 grams per mole in a weight ratio of said polypropylene to
nanoadditive ranging from 20:1 to 1:1. This can be carried out by
extrusion at 200.degree. C. The blend is microinjected at
230.degree. C. into dog-bone samples for testing. The exfoliation
of silicate nanolayers is stable after the blending, thereby
imparting to the nanocomposite resistance to breakage and
flammability and improved gas barrier properties and higher
crystallinity (45% compared to 34% for the original polypropylene).
In other words, the silicate layers are exfoliated and the
exfoliation is preserved despite extrusion at 200.degree. C. and
microinjection at 230.degree. C. The result is a nanocomposite
comprising polypropylene where elongation is increased at least 25%
and toughness is increased at least 10% while Young's modulus is
decreased less than 15%, compared to neat polyethylene. The
nanocomposites are useful in all those cases where polypropylene is
useful but contrary to the case with polypropylene, the
nanocomposite resists breakage and is not flammable.
[0052] We turn now to the fifth embodiment herein. This embodiment
is directed to group A functionalized organophilic polymers or
copolymers for use in preparation of the nanoadditive of the first
embodiment and these and their preparation are described above in
conjunction with description of the first embodiment.
[0053] We turn now to the sixth embodiment herein. This is directed
to a method for preparing the nanoadditive of the first embodiment
and comprises the step of reacting group A functionalized
organophilic polymer or copolymer with group B functionalized
silicate where group A and group B react to form silicate
covalently bonded to the polymer or copolymer. As above, group A is
selected from the group consisting of epoxide, cyclic anhydride,
lactone, amine, alcohol and acid, e.g., carboxylic acid, containing
moieties and group B is selected from the group consisting of
alkoxide, amine, acid, ester, aldehyde, ketone, and lactone
containing moieties; where when group A is epoxide containing
moiety, group B is selected from the group consisting of alkoxide,
amine and acid containing moieties; where when group A is cyclic
anhydride containing moiety, group B is selected from the group
consisting of alkoxide and amine containing moieties; where when
group A is lactone containing moiety, group B is selected from the
group consisting of alkoxide and amine containing moieties; where
when group A is amine containing moiety, group B is selected from
the group consisting of acid, ester, aldehyde, ketone and lactone
containing moieties; where when group A is alcohol containing
moiety, group B is selected from the group consisting of acid,
ester, aldehyde, ketone and lactone containing moieties; and when
group A is acid containing moiety, group B is selected from the
group consisting of alkoxide and amine containing moieties.
[0054] In one exemplified case, the group A functionalized polymer
or copolymer is epoxide functionalized poly(propylene-co-hexadiene)
having M.sub.n ranging from 5,000 to 2,000,000 grams per mole and
PDI ranging from 1.1 to 1.3, and the group B functionalized
silicate is 12-aminododecanoic acid or glycine ion exchanged under
acidic conditions with sodium montmorillonite so that group B is
anchored to silicate by an ammonium group.
[0055] In another exemplified case, the group A functionalized
polymer or copolymer is cyclic anhydride functionalized
polypropylene having M.sub.nranging from 5,000 to 4,000,000 and the
group B functionalized silicate is 12-aminododecanoic acid or
glycine or poly(propyleneglycol)bis(2-aminopropyl ether) as
described above is ion exchanged under acidic conditions with
Na-MMT so that group B is anchored to silicate by ammonium
group.
[0056] This method is described in conjunction with the first
embodiment and is exemplified in working examples herein.
[0057] We turn now to the seventh embodiment herein.
[0058] The method of the seventh embodiment is for preparing
nanocomposites of the second, third and fourth embodiments and
comprises the step of blending the nanoadditive of the first
embodiment with polypropylene having M.sub.n ranging from 5,000 to
4,000,000 grams per mole in a weight ratio of said polypropylene to
said nanoadditive ranging from 20:1 to 1:1. The blending can be
carried out by extruding admixture of nanoadditive and said
polypropylene at a temperature ranging from 160.degree. C. to
300.degree. C. Alternatives to extrusion blending are heating the
admixture of the nanoadditive and said polypropylene in an oven at
a temperature ranging from 1 90.degree. C. to 250.degree. C. either
under nitrogen or vacuum for two hours. This method is described in
conjunction with the second, third and fourth embodiments herein
and in working examples below.
[0059] The percentages of silicate content, polypropylene, and
nanoclay herein are by weight.
[0060] The invention is illustrated in the following working
examples:
WORKING EXAMPLES I
[0061] Epoxy containing moiety functionalized
poly(propylene-co-hexadiene copolymer) of M.sub.n of 36,000 grams
per mole and PDI of 1.14 (denoted PP-co-HD-epoxy) was prepared at
follows:
[0062] Vinyl functionalized poly(propylene-co-hexadiene) copolymer
was prepared by the method for forming vinyl functional
poly(propylene-co-hexadiene) as described in WO 2004/067589 A1 and
Publication No. US-2005-0239966, and particularly as described.
[0063] Acid containing moiety functionalized montmorillonite,
denoted MMT-COOH, was prepared by reacting sodium montmorillonite
(NAMMT) with 12-aminododecanoic acid, previously acidified with
hydrochloric acid. Particularly 0.11 g of 12-aminododecanoic acid
was added in 20 mL of H.sub.2O containing one equivalent HCl (with
respect to the carboxylic acid) and left stirring for 2 hours. The
resulting solution was added to a dispersion of 0.5 g MMT in 75 mL
of distilled water at 60 to 70.degree. C. with stirring for 4
hours. The modified MMT (designated MMT-COOH) was obtained after
filtration, washing with water, and freeze drying. The loading of
acid groups was 53.2 meq/100 g MMT based on TGA whereas the cation
exchange capacity (CEC) of the natural montmorillonite (MMT)
(Cloisite.RTM. Na.sup.+) was 92.6 meq/100 g.
[0064] Nanoadditive was prepared in solution as follows: A mixture
of PP-co-HD-epoxy and MMT-COOH (about 5:1 w/w) was refluxed in
chloroform for 24 hours under N.sub.2 flow and reaction product was
precipitated from MeOH. The precipitate was filtered and dried to
provide nanoadditive. The silicate content in the nanoadditive was
14.5% by weight.
[0065] Nanoadditive was prepared by a melt process as follows: An
admixture of PP-co-HD-epoxy and MMT-COOH (about 3:1, w/w) was
heated at 190.degree. C. either under nitrogen atmosphere or in a
vacuum oven for two hours. The nanoadditive product was obtained on
cooling to room temperature. The silicate content in the
nanoadditive was 19.6% by weight.
WORKING EXAMPLE II
[0066] Two different cyclic anhydride containing moiety
functionalized polypropylenes were purchased from Aldrich Chemical
Company.
[0067] In one case the polypropylene had M.sub.n of 3900 and PDI of
2.33, melting temperature of 156.degree. C. and acid number of 47
mg KOH/g. (M.sub.n data from Aldrich).
[0068] In the second case the polypropylene had M.sub.nof 83,300
and PDI of 1.94. It had a melt index of 115 g/10 min. (190.degree.
C./2.1 kg), melting temperature of 152.degree. C. and maleic
anhydride content of at least 0.6 wt %. (M.sub.n data
determined).
[0069] In the first case, the functionalized polypropylene was
denoted L-PP-g-MA, standing for lower molecular weight
polypropylene grafted maleic anhydride.
[0070] In the second case, the functionalized polypropylene was
denoted H-PP-g-MA, standing for higher molecular weight
polypropylene grafted maleic anhydride.
[0071] MMT-COOH is that described in Working Example I and was
prepared as in Working Example I.
[0072] Nanoadditive was prepared from L-PP-g-MA and MMT-COOH by a
melt process as follows: an admixture of L-PP-g-MA and MMT-COOH
(weight ratio of 5:1) was heated at 190.degree. C. under a nitrogen
atmosphere for 2 hours. The silicate content in the nanoadditive
was 15% by weight.
[0073] Nanoadditive was prepared from H-PP-g-MA and MMT-COOH by a
melt process as follows: an admixture of H-PP-g-MA and MMT-COOH
(weight ratio of 5:1) was heated at 190.degree. C. under a nitrogen
atmosphere for 2 hours. The silicate content in the nanoadditive
was 15% by weight.
WORKING EXAMPLE III
[0074] Nanocomposite was prepared by blending nanoadditive (14.5%
by weight silicate) of Working Example I and polypropylene
(isotactic, melt index of 0.5 g/10 min, m.p. 160-165.degree. C.,
d=0.900, from Aldrich) in a weight ratio of nanoadditive to
polypropylene of 1:9 by extruding admixture of nanoadditive and
polypropylene at 200.degree. C. for 1 to 3 minutes. Dog-bone shaped
samples, denoted samples A, were prepared by microinjection at
230.degree. C. The content of silicate (MMT) in the samples was
1.8% by weight (TGA).
WORKING EXAMPLE IV
[0075] Nanocomposite was prepared by blending nanoadditive of
Working Example II prepared by blending L-PP-g-MA, and the
commercial polypropylene described in Working Example III in a
weight ratio of nanoadditive to polypropylene of 1:6.5 by extruding
admixture of nanoadditive and commercial polypropylene at
200.degree. C. Dog-bone shaped samples, denoted samples B, were
prepared by microinjection at 230.degree. C. The content of
silicate in the samples was 2.5% by weight (TGA).
WORKING EXAMPLE V
[0076] Nanocomposite was prepared by blending nanoadditive of
Working Example II prepared by blending H-PP-g-MA, and the
commercial polypropylene described in Working Example III in a
weight ratio of nanoadditive to polypropylene of 1:6.5 by extruding
admixture of nanoadditive and commercial polypropylene at
200.degree. C. Dog-bone shaped samples, denoted samples C, were
prepared by microinjection at 230.degree. C. The content of
silicate in the samples was 2.5% by weight (TGA).
WORKING EXAMPLE VI
[0077] Mechanical testing was carried out using an Instron
tester.
[0078] Tests were carried out on Samples A (prepared in Working
Example III), Samples B (prepared in Working Example IV), Samples C
(prepared in Working Example V), Samples D (the commercial
polypropylene described in Working Example III extruded at
200.degree. C. and microinjected at 230.degree. C. into dog-bone
shapes), Samples E (blend of the commercial polypropylene and
PP-co-HD-epoxy described in Working Example I in a weight ratio of
10.6:1 extruded at 200.degree. C. and microinjected at 230.degree.
C. into dog-bone shapes), Samples F (a blend of the commercial
polypropylene and L-PP-g-MA described in Working Example II when
the L-PP-g-MA is present in an amount of 10% by weight at
200.degree. C. and microinjected at 230.degree. C. into dog-bone
shapes), Samples G (a blend of the commercial polypropylene and
H-PP-g-MA described in Working Example II where the H-PP-g-MA is
present in an amount of 10% by weight, extruded at 200.degree. C.
and microinjected into dog-bone shapes at 230.degree. C., Samples H
(the blend of samples F also containing 2.5% by weight MMT-COOH
extruded at 200.degree. C. and microinjected at 230.degree. C. into
dog-bone shapes), Samples I (the blend of Samples G also containing
2.5% by weight MMT-COOH extruded at 200.degree. C. and
microinjected at 230.degree. C. into dog-bone shapes).
[0079] Results at crosshead speed of 5 mm/min (standard speed) are
set forth in Table 1 below. TABLE-US-00001 TABLE 1 Samples A D E F
G H I B C Elongation 608.64 363.68 248.69 373.26 307.17 378.34
80.54 398.50 101.78 (%) (+67.36%) (-31.62%) (+2.6%) (-15.5%)
(+4.0%) (-77.9%) (+9.6%) (-72%) Modulus 915.27 1082.22 1065 944.50
960.35 1154.53 1097.53 1019.11 1099.90 (Young) (-15.43%) (-1.6%)
(-12.7%) (-11.3%) (+6.7%) (+1.4%) (-5.8%) (+1.6%) (MPa) Tensile
38.13 47.47 43.61 39.14 42.29 41.47 43.60 41.56 46.02 Strength
(-19.68%) (-8.1%) (-17.5%) (-10.9%) (-12.6%) (-8.2%) (-12.4%)
(-3.0%) (MPa) Toughness 196.59 158.55 101.46 135.32 121.29 147.46
32.75 155.60 44.03 (MPa) (+23.99%) (-36.0%) (-14.7%) (-23.5%)
(-7.0%) (-79.3%) (-1.9%) (-72.2%)
[0080] Results at crosshead speed of 20 mm/min (standard speed) are
given in Table 2 below. TABLE-US-00002 TABLE 2 Samples A D F G H I
B C Elongation 296 324 236 241 178 67 386 412 (%) (-27.2%) (-25.6)
(-45.1%) (-79.3%) (+19.1%) (+27.2%) Modulus 821.5 912.3 1089 1175.7
1143.5 1221 1031 1043 (Young) (+19.4%) (+28.9%) (+25.3%) (+32.9%)
(+13%) (+14.3%) (MPa) Tensile 40.4 47.0 42.3 51.4 43.8 45.7 42.9
45.5 Strength (-10%) (+9.4%) (-6.8%) (-2.8%) (-8.7%) (-3.2%) (MPa)
Toughness 96.3 125.3 99.3 149 (?) 84.5 28.1 143.7 142.8 (MPa)
(-20.8%) (+19%) (-32.6%) (-77.6%) (+14.7%) (+14%)
Variations
[0081] The foregoing description of the invention has been
presented describing certain operable and preferred embodiments. It
is not intended that the invention should be so limited since
variations and modifications thereof will be obvious to those
skilled in the art, all of which are within the spirit and scope of
the invention.
* * * * *